Nano-Sized Tin Particle/Carbon Nanofiber Composites As Anode Materials for Lithium-Ion Batteries

In recent developments of the new anode materials for high performance Lithium-ion batteries (LIBs), metallic tin (Sn) material, which easily alloys with lithium, has attracted much attention and has been widely seen as a potential substitute for the conventional graphite electrode due to its high theoretically reversible specific capacity of about 992mAhg^-1 as Li_4.4Sn. However, its practical usage in LIBs has been greatly hampered by the extremely large volume change of about 260% when Sn alloys with Li to form Li_4.4Sn during Li⁺ insertion/extraction cycles, which leads to pulverization of the electrode and very rapid capacity fading. In our present work, to overcome this problem, we proposed a profound new strategy of disperseing nano-sized Sn particles in carbon nanofibers (CNFs) to prepare a novel nano-sized Sn@CNF composite as an anode material for LIBs by using electrospinning techniques and heating treatment. The effect of heating treatment on the phase structure of Sn and the electrochemical performance of the Sn@CNF composites were investigated. Amorphous and crystalline Sn@CNFs composites were obtained by changing heating temperature or time. The electrochemical performance results of the composites show that the amorphous Sn@CNFs anode exhibits much higher capacity and more superior cycling stability than the crystalline Sn@CNFs anode material. Such a composite opens up a possibility of fabricating higher energy-density lithium-ion batteries.